This invention relates to a developing apparatus for developing semiconductor wafers, glass substrates for liquid crystal displays, glass substrates for photomasks, and substrates for optical disks (hereinafter called simply “substrates”). More particularly, the invention relates to a technique for checking consumption of a developer by supplying the developer to substrates efficiently.
Conventionally, this type of apparatus includes a spin chuck for rotatably supporting a substrate, a slit nozzle for supplying a developer in a belt-like shape to the substrate, and a moving mechanism for moving the slit nozzle. This apparatus supplies the developer in the belt-like shape spirally to the substrate while spinning the substrate and moving the slit nozzle. Compared with the case of forming a puddle of the developer on the substrate to develop the substrate, this apparatus can reduce consumption of the developer (as disclosed in Japanese Unexamined Patent Publication No. 2005-210059, for example).
The conventional apparatus with the above construction has the following drawbacks.
The developer discharged down from the slit nozzle takes the belt-like shape. The belt-like shape of the developer tends to deform with variations in the flow rate of the developer supplied to the slit nozzle. Specifically, the belt-like shape of the developer narrows or splits into two or more strips. In such a case, it becomes difficult to cause the developer to impinge in desired positions or ranges on the substrate. Even though the developer is supplied spirally, there arises an inconvenience that the developer cannot be supplied without gaps over the entire surface of the substrate. In order to avoid such an inconvenience, it is conceivable to supply the developer in an excess quantity. In this case, consumption of the developer is increased.